HYDROACOUSTICS
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Application of maximum length sequence in silent sonar

pp. 143-152, vol. 15, 2012

Jacek Marszal
Gdansk University of Technology, Faculty of Electronics , Telecomunications and Informatics, Department of Marine Electronic Systems, Gdansk, Poland

Roman Salamon
Gdansk University of Technology, Faculty of Electronics, Telecommunication and Informatics, Department of Marine Electronic Systems, Gdansk, Poland

Lech Kilian
Gdansk University of Technology, Faculty of Electronics, Telecommunication and Informatics, Department of Marine Electronic Systems, Gdansk, Poland

Key words: wide bandwidth; Doppler effect

Abstract: Silent sonars are designed to reduce the distance over which their sounding pulses can be detected by intercept sonars. In order to meet this objective, we can use periodical sounding signals that have low power, a very long duration and wide spectrum. If used in the silent sonar’s receiver, matched filtration ensures very good detection of motionless or slow moving targets. However, it is more difficult to detect echo signals of fast moving targets with Doppler effect causing significant error in target distance measurements. In an effort to find signals that can better resist Doppler effect, maximum length sequence was tested for its application in silent sonar. It has an elementary signal which includes linear frequency modulation. It was demonstrated that the signal produces much better results than those obtained with simple frequency modulation signals.

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© Polish Acoustical Society - Gdansk Department, Polish Academy of Sciences. This work is licensed under the Creative Commons Attribution-NonCommercial-ShareAlike 3.0 Unported. (CC BY-NC-SA 3.0)